Methods and apparatus to recover rotorcraft

ABSTRACT

Methods and apparatus to recover rotorcraft are disclosed. A disclosed example apparatus includes a rotor of a vehicle, a rotatable hub to support the rotor, and a rotor hook disposed on the rotor. The rotor hook has a groove to receive a recovery line. The rotor is to contact the recovery line when the vehicle is flown toward the recovery line.

FIELD OF THE DISCLOSURE

This disclosure relates generally to aircraft and, more particularly, tomethods and apparatus to recover rotorcraft.

BACKGROUND

In recent years, aircraft, such as rotorcraft, have been implemented asunmanned aerial vehicles (UAVs) or drones to fly across significantdistances to transport payloads (e.g., packages, supplies, equipment,etc.) or gather information. Some rotorcraft UAVs land on landing pads.Features and/or components implemented to allow these rotorcraft UAVs toland on landing pads can add weight, drag, complexity and cost to a UAV.Further, a landing process of a UAV rotorcraft can take a significantamount of time.

SUMMARY

An example apparatus includes a rotor of a vehicle, a rotatable hub tosupport the rotor, and a rotor hook disposed on the rotor. The rotorhook has a groove to receive a recovery line. The rotor is to contactthe recovery line when the vehicle is flown toward the recovery line.

An example method of recovering an aircraft includes moving the aircrafttoward a suspended recovery line, contacting a portion of a rotor of theaircraft with the recovery line, and drawing the recovery line to arotor hook based on a rotation of the rotor.

An example aircraft includes a rotor assembly. The rotor assemblyincludes a first rotor having a first rotor hook with a first groove,and a second rotor having a second rotor hook with a second groove,where an opening of the second groove faces a direction opposite anopening of the first groove, and where at least one of the first orsecond grooves is to receive a recovery line when the rotor assemblycontacts the recovery line.

An example apparatus includes means for generating a lift of arotorcraft. The means for generating the lift has means for restraininga recovery line.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an example aircraft in which examples disclosed herein can beimplemented.

FIG. 2 illustrates an example rotor assembly in accordance with theteachings of this disclosure.

FIGS. 3A and 3B are detailed views of example rotor hooks that can beimplemented in examples disclosed herein.

FIGS. 4A-4C illustrate example steps of a rotorcraft recovery.

FIG. 5 is a flowchart representative of an example method to implementexamples disclosed herein.

The figures are not to scale. Instead, the thickness of the layers orregions may be enlarged in the drawings. In general, the same referencenumbers will be used throughout the drawing(s) and accompanying writtendescription to refer to the same or like parts. As used in this patent,stating that any part is in any way on (e.g., positioned on, located on,disposed on, or formed on, etc.) another part, indicates that thereferenced part is either in contact with the other part, or that thereferenced part is above the other part with one or more intermediatepart(s) located therebetween. Stating that any part is in contact withanother part means that there is no intermediate part between the twoparts.

DETAILED DESCRIPTION

Methods and apparatus to recover rotorcraft are disclosed. Some unmannedaerial vehicles (UAVs) are implemented as rotorcraft. These UAVrotorcraft often require landing components and/or landing supportsystems that can adversely impact aerodynamic properties and/or weightand, thus, increase fuel consumption while reducing flight range.Further, UAV rotorcraft landing can take a significant amount of time toland.

Some known fixed wing UAVs are recovered by UAV recovery systems, whichcan subject the UAVs to significant loads due to a sudden decelerationduring an impact with a recovery device. These significant loads cancause damage or necessitate strengthening components or features,thereby increasing cost and weight of the UAVs.

Example disclosed herein provide cost-effective recovery of rotorcraft(e.g., UAV rotorcraft) with little or negligible impact forces.Accordingly, examples disclosed herein enable relatively light-weightrotorcraft that do not necessitate landing components and/or reinforcingcomponents for withstanding significant impact forces during recovery.Accordingly, weight is saved and, in turn, a flight range can beincreased based on increased fuel efficiency. Further, examplesdisclosed enable rotorcraft to be recovered relatively quickly without aneed for precise navigational control.

As used herein, the term “rotor hook” refers to a component and/orassembly that is mounted on or proximate a rotor and used to retain arecovery line, rope and/or cable. As used herein, the term “lock” refersto a mechanical and/or electromechanical device, component and/orassembly used to restrain or lock one component to another.

FIG. 1 is an example aircraft 100 in which examples disclosed herein canbe implemented. In this particular example, the aircraft 100 isimplemented as a UAV rotorcraft. The aircraft 100 of the illustratedexample includes a nose portion (e.g., a navigation or control portion)101, a fuselage or body 102, a tail 104 with a tail rotor 106 and a mainrotor (e.g., a main rotor assembly) 108. In some examples, the aircraft100 includes landing struts or supports 110.

In operation, the aircraft 100 is self-navigated and/or controlled viaan external network communicatively coupled to the nose portion 101. Todirect movement of the aircraft 100 during flight, the rotor assembly108 spins to generate a lift of the aircraft 100 while the tail rotor106 counteracts torque from the main rotor 108. When the aircraft 100 ismoved toward a landing pad or surface during a landing maneuver, themain rotor 108 and the tail rotor 106 are controlled in a coordinatedmanner to enable a controlled descent so that the struts or supports 110are brought into contact with the landing pad/surface. This controlleddescent can take a significant amount of time.

While the example of FIG. 1 is shown in the context of a UAV rotorcraft,examples disclosed herein can be applied to any vehicle with a rotor ora propeller, such as, but not limited to, a manned rotorcraft, a fixedwing aircraft (e.g., a fixed wing aircraft with a propeller), a boat, asubmarine, a quadcopter, a gyrocopter, vertical takeoff and landing(VTOL) aircraft, short takeoff and landing (STOL) aircraft, etc. In someexamples disclosed herein, the struts or supports 110 are notimplemented.

FIG. 2 illustrates the example rotor assembly 108 in accordance with theteachings of this disclosure. The rotor assembly 108 of the illustratedexample includes a rotor hub (e.g., a rotating hub) 202, rotors (e.g.,means for generating lift) 204 (hereinafter 204 a, 204 b, etc.), androtor hooks (e.g., means for restraining) 206 (hereinafter 206 a, 206 b,etc.) with corresponding grooves 207 (hereinafter 207 a, 207 b). In thisexample, the rotors 204 a, 204 b are staggered relative to one another(e.g., offset along a center axis). Further, the rotors 204 a, 204 binclude respective outer portions 208 a, 208 b, respectively, withleading edges 209 in this example.

To engage at least one of the rotor hooks 206 a, 206 b with a recoveryline (e.g., a recovery rope, a recovery cable, etc.) 402 (shown in FIG.4), the aircraft 100 is flown and/or hovered proximate to the recoveryline 402 with the rotors 204 a, 204 b rotating along a directiongenerally indicated by an arrow 210, thereby causing the recovery line402 to contact either the portion 208 a or the portion 208 b. As aresult, at least a portion of the recovery line 402 contacts and movesalong the leading edge 209 in a direction generally indicated by anarrow 212. Further, rotation of the rotors 204 a, 204 b moves therecovery line 402 into at least one the grooves 207 a, 207 b of therespective rotor hooks 206 a, 206 b to constrain the aircraft 100 to therecovery line 402. In particular, as the recovery line 402 is coupledand/or constrained to the at least one of the rotor hooks 206 a, 206 b,the aircraft 100 is decelerated to a rest. In this example, the grooves207 a, 207 b have corresponding openings that face in opposingdirections to facilitate multiple engagement points with the recoveryline 402. In particular, the recovery line 402 can engage both of thehooks 206 a, 206 b in this example. While in this example, the recoveryline 402 contacts either portion 208 a or the portion 208 b, in otherexamples, the recovery line 402 can initially contact any portion of therotor hub 202 or the leading edges 209. In such examples, the rotationof the rotors 204 a, 204 b similarly moves the recovery line 402 to atleast one of the rotor hooks 206 a, 206 b. In the illustrated example ofFIG. 2, fairings 211 a, 211 b are disposed between the rotor hub 202 andthe respective rotor hooks 206 a, 206 b to enable the recovery line 402to slide from the rotor hub 202 and into one of the grooves 207 a, 207 bof one of the rotor hooks 206 a, 206 b. In other examples, fairings maynot be provided.

In some other examples, the rotor hooks 206 a, 206 b are implemented inthe tail rotor 206 instead. While two of the rotor hooks 206 a, 206 bare shown in this example, any appropriate number of rotor hooks 206 canbe used instead (e.g., one, three, four, five, six, seven, eight, nine,etc.). In some other examples, the rotor hooks 206 a, 206 b areimplemented on a fixed wing aircraft propeller or rotors of a quadcopter(e.g., a UAV quadcopter).

FIGS. 3A and 3B are detailed views of example rotor hooks 302, 330,respectively, both of which can be implemented in examples disclosedherein. In particular, the examples of FIGS. 3A and 3B can be used toimplement any of the rotor hooks 206 shown and described above inconnection with FIG. 2. Turning to FIG. 3A, the example rotor hook 302is shown. According to the illustrated example, the rotor hook 302includes a curved support body 304, a mounting flange 306 with fasteneropenings 307, and a groove or channel (e.g., a capture groove, a ropegroove, etc.) 308. According to the illustrated example, the groove 308includes a narrow portion 309, a wider recess portion 310 and an entryportion 311. The example rotor hook 302 also includes a curved lead-inportion 312. In some examples, the rotor hook 302 includes a lock (e.g.,a pivot lock, a pivoting lock, a pivoting lever, a means for locking)314 that rotates about a pivot 316.

To retain the recovery line 402 in the rotor hook 302, the recovery line402 is brought into the entry portion 311 as the rotors 204 a, 204 bcontact the recovery line 402. The spinning motion of the rotors 204 a,204 b causes the recovery line 402 to contact the lock 314 and, in turn,rotate the lock 314 about the pivot 316. The example lock 314 isrotationally constrained to rotate at a defined angular range, asgenerally indicated by an angular range 320. Subsequent to the recoveryline 402 moving past the lock 314, the recovery line 420 is drawn towardthe recess portion 310 and into the narrow portion 309 based on themovement of the rotors 204 a, 204 b. In this example, the recovery line402 is prevented from moving out from the lock 314 based on theaforementioned angular range of the lock 314. In other words, movementof the recovery line 402 from the groove 308 toward the lock 314 doesnot cause the lock 314 to rotate away from the recovery line 402, inthis example. In some examples, manual movement or rotation of the lock314 is necessitated to release the recovery line 402.

In some examples, the lock 314 is spring-loaded. In some other examples,the lock 314 relies on a linear motion instead of an angular rotationalmotion (e.g., a linear sliding lock or clasp, etc.). In some examples,the rotor hook 302 includes multiple ones of the locks 314 that arespaced along a length of the groove 308 (e.g., evenly spaced orstaggered). In such examples, the multiples ones of the locks 314 can bepivoting. In other examples, the rotor hook 302 does not implement anyof the locks 314.

In some examples, the channel 308 has a width (e.g. a groove width) ofapproximately 0.052 inches to 0.060 inches (e.g., 0.056 inches), asgenerally indicated by a dimension 322 shown in FIG. 3A, while therecess portion 310 has a width of approximately 0.136 to 0.144 inches(e.g., 0.140 inches), as generally indicated by a dimension 324, and theexample recovery line 402 has a diameter of approximately 0.250 inches.In particular, the recovery line 402 is compressed to fit within thechannel 308 and the recess portion 310. In such examples, a ratio of thewidth of the channel 308 to the diameter of the recovery line 402 canrange from approximately 0.20 (e.g., 0.208) to 0.24. For example, theratio may be 0.224. Further, a ratio of the width of the recess portion310 to the diameter of the recovery line 402 can range fromapproximately 0.54 (e.g., 0.544) to 0.58 (e.g., 0.576). For example, theratio can be 0.56. However, these dimensions are only examples and anyappropriate dimensions based on application and/or desired designparameters can be used instead.

Turning to FIG. 3B, the example rotor hook 330 is similar to the rotorhook 302 described above in connection with FIG. 3A but, instead,includes a lock (e.g., a clasping lock, a rotatable locking clasp, arotatable cam, etc.) 331 that acts as a clasp, in this example. Therotor hook 302 also includes a support body 332, and a mounting flange336.

The lock 331 of the illustrated example exhibits a generally rampedshape. The example lock 331 includes a first ramped portion 342, a roundedge portion (e.g., a round divot, a round scallop, etc.) 344, a secondramped portion 346 positioned proximate the round edge portion 344, anda pivot 348. In some examples, the lock 331 includes a retainer 349.Additionally or alternatively, the lock 331 is spring-loaded and/or theretainer 349 acts as a spring to affect an angular rotation of the lock331.

In operation, when the recovery line 402 contacts the first rampedportion 342, the lock 331 rotates, thereby enabling the recovery line402 to be placed in the round edge portion 344 and into a channel 338based on an additional rotation of the lock 331, for example. In otherwords, the lock 331 can exhibit a ratcheting motion when the recoveryline 402 is placed into the rotor hook 330 and retained by the lock 331.In some examples, multiple portions of the recovery line 402 are held bythe lock 331.

In some examples, the channel 338 has a width of approximately 0.130inches to 0.150 inches (e.g., 0.140 inches), as indicated by a dimension350 shown in FIG. 3B, while the recovery line 402 has a diameter of0.250 inches. In such examples, a ratio of the width to the diameter ofthe channel 338 can range from approximately 0.52 to 0.60 (e.g., theratio can be 0.56). However, these dimensions are only examples and anyappropriate dimensions based on application and/or desired designparameters can be used instead.

FIGS. 4A-4C illustrate example steps of a rotorcraft recovery. Turningto FIG. 4A, the aircraft 100 is shown flying toward the aforementionedrecovery line 402. In this example, the recovery line 402 is implementedas a rope (e.g., an elastic rope) or cable and shown supported by asupport structure (e.g., a fixed support structure) 404.

According to the illustrated example of FIG. 4A, the rotors 204 arespinning along with the corresponding rotor hooks 206, and the aircraft100 moves to contact the recovery line 402 with the rotors 204. Forexample, distal portions or ends of the rotors 204 are brought intocontact with the recovery line 402 based on motion of the aircraft 100.

In some examples, the recovery line 402 is suspended from anothervehicle or vessel (e.g., a UAV, a boat, an aircraft, submarine, etc.).In other examples, the recovery line 402 is suspended from a building orother land-based structure. In other examples, the recovery line 402 isheld taut at its opposite ends.

FIG. 4B depicts the aircraft 100 as the recovery line 402 is drawninward toward the rotor hub 202 by the rotors 204. As a result, therecovery line 402 slides towards the rotor hooks 206. According to theillustrated example, the aircraft 100 undergoes deceleration as thespinning rotors 204 engage the recovery line 402.

FIG. 4C depicts the aircraft 100 as additional rotation of the rotors204 causes the recovery line 402 to be wrapped around the rotor hub 202,for example. According to the illustrated example, the aircraft 100 isrestrained and/or held by the recovery line 402. In other words, therecovery line 402 is wound around the aircraft 100 to suspend theaircraft 100 above the ground.

FIG. 5 is a flowchart representative of an example method 500 toimplement examples disclosed herein. The example method 500 begins asthe aircraft 100, which is implemented as a UAV rotorcraft in thisexample, has completed a mission and is to be recovered.

According to the illustrated example, the aircraft 100 is moved towardthe recovery line 402 (block 502). In this example, the aircraft 100 isnavigated so that the portion 208 of the rotor 204 is directed towardthe recovery line 402. However, in other examples, any portion of therotor hub 202 or the leading edges 209 can be directed at the recoverline 402.

In this example, as the aircraft 100 is moved toward the recovery line402, the portion 208 of the rotor 204 engages and/or contacts therecovery line 402 (block 504).

Next, the example rotor 204 continues to spin to draw the recovery line402 into the rotor hook 206 (block 506). In particular, the recoveryline 402 is moved into the corresponding groove 207 of the rotor hook206 as the rotor 204 spins after contacting the recovery line 402. Insome examples, the recovery line is caused to wrap around the aircraft100.

The aircraft 100 of the illustrated example is captured in the recoveryline 402 (block 508). In particular, the aircraft 100 is suspended aboveground based on the recovery line 402 being wound around the aircraft100.

Next, the aircraft 100 is removed from the recovery line 402 (block 510)and the process ends. In this example, the recovery line 402 is removedfrom the rotor hooks 206 and unwound from the aircraft 100 while heaircraft 100 is suspended from the ground.

“Including” and “comprising” (and all forms and tenses thereof) are usedherein to be open ended terms. Thus, whenever a claim employs any formof “include” or “comprise” (e.g., comprises, includes, comprising,including, having, etc.) as a preamble or within a claim recitation ofany kind, it is to be understood that additional elements, terms, etc.may be present without falling outside the scope of the correspondingclaim or recitation. As used herein, when the phrase “at least” is usedas the transition term in, for example, a preamble of a claim, it isopen-ended in the same manner as the term “comprising” and “including”are open ended. The term “and/or” when used, for example, in a form suchas A, B, and/or C refers to any combination or subset of A, B, C such as(1) A alone, (2) B alone, (3) C alone, (4) A with B, (5) A with C, (6) Bwith C, and (7) A with B and with C. As used herein in the context ofdescribing structures, components, items, objects and/or things, thephrase “at least one of A and B” is intended to refer to implementationsincluding any of (1) at least one A, (2) at least one B, and (3) atleast one A and at least one B. Similarly, as used herein in the contextof describing structures, components, items, objects and/or things, thephrase “at least one of A or B” is intended to refer to implementationsincluding any of (1) at least one A, (2) at least one B, and (3) atleast one A and at least one B. As used herein in the context ofdescribing the performance or execution of processes, instructions,actions, activities and/or steps, the phrase “at least one of A and B”is intended to refer to implementations including any of (1) at leastone A, (2) at least one B, and (3) at least one A and at least one B.Similarly, as used herein in the context of describing the performanceor execution of processes, instructions, actions, activities and/orsteps, the phrase “at least one of A or B” is intended to refer toimplementations including any of (1) at least one A, (2) at least one B,and (3) at least one A and at least one B.

Example 1 includes an apparatus having a rotor of a vehicle, a rotatablehub to support the rotor, and a rotor hook disposed on the rotor, therotor hook having a groove to receive a recovery line. The rotor is tocontact the recovery line when the vehicle is flown toward the recoveryline.

Example 2 includes the apparatus of Example 1, and further includes alock coupled to the rotor hook to restrain the recovery line to therotor hook.

Example 3 includes the apparatus of Example 2, where the lock includes apivoting lever.

Example 4 includes the apparatus of Example 1, where a ratio of a widthof the groove to a diameter of the recovery line is between 0.20 and0.24.

Example 5 includes the apparatus of Example 1, where the rotor hook isdisposed proximate the rotatable hub.

Example 6 includes the apparatus of Example 1, where the recovery lineis to contact a leading edge of the rotor and move toward the rotor huband into the rotor hook.

Example 7 includes the apparatus of Example 6, where the rotor is tocontact the recovery line at a distal end of the rotor.

Example 8 includes the apparatus of Example 1, where the vehicle is anunmanned aerial vehicle (UAV).

Example 9 includes a method that includes moving the aircraft toward asuspended recovery line, contacting a portion of a rotor of the aircraftwith the recovery line, and drawing the recovery line to a rotor hookbased on a rotation of the rotor.

Example 10 includes the method of Example 9, and further includesrestricting, via a lock, the recovery line to the rotor hook.

Example 11 includes the method of Example 10, where restraining therecovery line includes rotating a pivoting lever to constrain therecovery line in a groove of the rotor hook.

Example 12 includes the method of Example 9, where the portion of therotor includes a distal portion of the rotor.

Example 13 includes the method of Example 9, where drawing the recoveryline to a rotor hook including moving the recovery line toward arotating hub.

Example 14 includes an aircraft having a rotor assembly. The rotorassembly includes a first rotor having a first rotor hook with a firstgroove, and a second rotor having a second rotor hook with a secondgroove, where an opening of the second groove faces a direction oppositean opening of the first groove. At least one of the first or secondgrooves is to receive a recovery line when the rotor assembly contactsthe recovery line.

Example 15 includes the aircraft of Example 14, and further includes alock to retain the recovery line.

Example 16 includes the aircraft of Example 15, where the lock includesa pivoting lever.

Example 17 includes the aircraft of Example 16, where the pivoting leveris spring-loaded.

Example 18 includes the aircraft of Example 14, where a ratio of agroove width of each of the first and second grooves to a diameter ofthe recovery line is between 0.20 and 0.24.

Example 19 includes the aircraft of Example 14, where the rotor assemblydefines a propeller of a fixed wing aircraft.

Example 20 includes the aircraft of Example 14, where the first rotorhook is positioned at a proximate end of the first rotor and the secondrotor hook is positioned at proximate end of the second rotor.

Example 21 includes an apparatus having means for generating a lift of arotorcraft. The means for generating the lift has means for restraininga recovery line.

Example 22 includes the apparatus of Example 21, and further includesmeans for locking the recovery line to the means for restraining therecovery line.

From the foregoing, it will be appreciated that example methods,apparatus and articles of manufacture have been disclosed that provideeffective recovery of rotorcraft with little or negligible impactforces. Accordingly, examples disclosed herein enable relativelylight-weight rotorcraft that do not necessitate landing componentsand/or reinforcing components to withstand significant impact forcesduring recovery. Further, these weight reductions can have positiveeffects on aerodynamic properties and, thus, increase a flight range.

Although certain example methods, apparatus and articles of manufacturehave been disclosed herein, the scope of coverage of this patent is notlimited thereto. On the contrary, this patent covers all methods,apparatus and articles of manufacture fairly falling within the scope ofthe claims of this patent. While examples disclosed herein are shownrelated to UAV rotorcraft, examples disclosed herein can be applied toany rotorcraft or rotor applications, such as boats, fixed-wingaircraft, submersibles, etc.

What is claimed is:
 1. An apparatus comprising: a rotor of a vehicle; arotatable hub to support the rotor; and a rotor hook disposed on therotor, the rotor hook having a groove to receive a recovery line, therotor to contact the recovery line when the vehicle is flown toward therecovery line.
 2. The apparatus as defined in claim 1, further includinga lock coupled to the rotor hook to restrain the recovery line to therotor hook.
 3. The apparatus as defined in claim 2, wherein the lockincludes a pivoting lever.
 4. The apparatus as defined in claim 1,wherein a ratio of a width of the groove to a diameter of the recoveryline is between 0.20 and 0.24.
 5. The apparatus as defined in claim 1,wherein the rotor hook is disposed proximate the rotatable hub.
 6. Theapparatus as defined in claim 1, wherein the recovery line is to contacta leading edge of the rotor and move toward the rotor hub and into therotor hook.
 7. The apparatus as defined in claim 6, wherein the rotor isto contact the recovery line at a distal end of the rotor.
 8. Theapparatus as defined in claim 1, wherein the vehicle is an unmannedaerial vehicle (UAV).
 9. A method of recovering an aircraft, the methodcomprising: moving the aircraft toward a suspended recovery line;contacting a portion of a rotor of the aircraft with the recovery line;and drawing the recovery line to a rotor hook based on a rotation of therotor.
 10. The method as defined in claim 9, further includingrestricting, via a lock, the recovery line to the rotor hook.
 11. Themethod as defined in claim 10, wherein restraining the recovery lineincludes rotating a pivoting lever to constrain the recovery line in agroove of the rotor hook.
 12. The method as defined in claim 9, whereinthe portion of the rotor includes a distal portion of the rotor.
 13. Themethod as defined in claim 9, wherein drawing the recovery line to arotor hook including moving the recovery line toward a rotating hub. 14.An aircraft comprising: a rotor assembly including: a first rotor havinga first rotor hook with a first groove, and a second rotor having asecond rotor hook with a second groove, wherein an opening of the secondgroove faces a direction opposite an opening of the first groove, andwherein at least one of the first or second grooves is to receive arecovery line when the rotor assembly contacts the recovery line. 15.The aircraft as defined in claim 14, further including a lock to retainthe recovery line.
 16. The aircraft as defined in claim 15, wherein thelock includes a pivoting lever.
 17. The aircraft as defined in claim 16,wherein the pivoting lever is spring-loaded.
 18. The aircraft as definedin claim 14, wherein a ratio of a groove width of each of the first andsecond grooves to a diameter of the recovery line is between 0.20 and0.24.
 19. The aircraft as defined in claim 14, wherein the rotorassembly defines a propeller of a fixed wing aircraft.
 20. The aircraftas defined in claim 14, wherein the first rotor hook is positioned at aproximate end of the first rotor and the second rotor hook is positionedat proximate end of the second rotor.
 21. An apparatus comprising: meansfor generating a lift of a rotorcraft, the means for generating the lifthaving means for restraining a recovery line.
 22. The apparatus asdefined in claim 21, further including means for locking the recoveryline to the means for restraining the recovery line.